server/v2/cometbft commands should support both json and yaml output

[kocubinski]

see these TODOs (and possibly others).

cosmos-sdk/server/v2/cometbft/commands.go

Lines 206 to 208 in 6e54d78

	// return clientCtx.PrintProto(blocks) // TODO: previously we had this, but I think it can be replaced with a simple json marshal.
	// We are missing YAML output tho.
	bz, err := protojson.Marshal(blocks)

cosmos-sdk/server/v2/cometbft/commands.go

Line 66 in 6e54d78

// TODO: figure out yaml and json output

[facundomedica]

I do remember these comments now. I think it was that we were previously using the codec for json. Then the YAML I think it was just a matter of having an output flag there, which previously was being imported from the sdk.